1. Field of the Invention
The present invention relates to a linear motor.
2. Description of the Related Art
Referring to FIG. 2, a front view of a prior art linear motor 5 is shown. The linear motor 5 includes: an electrically controlled actuator 6, an elastic member 7 connected to the electrically controlled actuator 6, an insulating piece 8 positioned above the elastic member 7, and a pair of power supply terminals 9 soldered to the elastic member 7. The electrically controlled actuator 6 comprises a fixed element 61, a movable element 62 positioned on the fixed element 61, and an electrical unit 63 positioned around the outside of the movable element 62. FIG. 1 shows a top view of a prior art elastic member 7 as described above, which comprises a fixed portion 71, an elastic portion 72 linked to the fixed portion 71, and a movable portion 73 connected to the elastic portion 72. As shown in FIG. 2, the elastic member 7 and the insulating piece 8 are positioned sequentially between the fixed element 61 and the movable element 62 of the electrically controlled actuator 6. The insulating piece 8 prevents the elastic member 7 from electrically communicating with other metal components; moreover, the insulating piece 8 provides additional strength to press on the elastic member 7 so that it can be secured at a proper position.
The fixed portion 71 of the elastic member 7 is connected to the fixed element 61 of the actuator 6. The movable portion 73 of the elastic member 7 is connected to the movable element 62 of the actuator 6. The pair of power supply terminals 9 and the elastic member 7 are soldered together, while the elastic portion 72 also electrically communicates with the electrical unit 63 of the actuator 6 to transmit electricity thereto. When an external power source (not shown) is coupled to the pair of power supply terminals 9, power will flow sequentially through the terminals 9 and the elastic member 7 to the electrical unit 63 of the actuator 6, thereby leading to an axial displacement of the movable element 62. This axial displacement then moves the movable portion 73 of the elastic member 7, further leading to a linear displacement of the elastic portion 72.
FIG. 3 shows a top view of another prior art elastic member 10. A pair of power supply terminals 104 is formed integrally into the elastic member 10 to become one piece; hence, the step in which terminals 104 are soldered to the elastic member 10 can be eliminated. The elastic member 10 comprises a fixed portion 101, an elastic portion 102, a movable portion 103, and a pair of power supply terminals 104.
Both of the prior art elastic member 7 and 10 described above are flat springs with an even thickness. As miniaturization is a continuing trend in the production of electronic products, components like the elastic members 7 and 10 may be required to have smaller spring constants, and their thicknesses will become smaller as a result. However, as the spring constant of an elastic member reduces, so does its stiffness; in consequence, the elastic member tends to rupture more easily. It is thus important to manage the balance between the spring constant and the stiffness of an elastic member, particularly in a design where the elastic member and power supply terminals are combined together. In this kind of design, generally, the elastic member is expected to have a relatively small spring constant; however, this may lead to a smaller stiffness for the power supply terminals. Since power supply terminals may have to be bent during assembly, they will be subject to rupture more easily with a smaller stiffness, thereby causing wastes that increase the production cost. Moreover, as the elastic member 10 and the power supply terminals 104 both become thinner, poor electrical contact between the terminals 104 and an external power source tend to happen more frequently.
As such, there exists a need in the art to develop an improved elastic member that has a reduced thickness and overcomes the drawback of easy rupturing and poor electrical contact at the power supply terminals on the elastic member. Such an improved elastic member may effectively lower the production cost accordingly.